Red Lobster CEO Kim Lopdrup told Business Insider that chasing the young crowd was never part of the chain's strategy. "Red Lobster is not the first place people think of as a favorite restaurant for millennials," he said, adding that they "have not been explicitly targeting millennials. We've just been focusing on making improvements overall."

This surprising development is good news for the chain, which has recently experienced some serious economic ups and downs, sales dropping 5.6 percent in the fourth quarter of 2014, and 9 percent the prior quarter. However, after being taken private nearly 2 years ago, Red Lobster has seen positive sales for the last six quarters straight, aided by the additions of trendier food items like lobster tacos, more wood-grilled items, and fancier fare like wild-caught Alaska Sockeye Salmon.

The chain has also emphasized the importance of having a quality, sit-down meal during a time when many restaurants are pushing take-out options. This idea, which is promoted by Red Lobster's ability to accomodate large parties, has likely appealed to millennials who crave authentic dining experiences, rather than mere calories. "Millennials are very social," Lopdrop said. "They like to share experiences with friends and they like to dine in groups."

The Nation's Restaurant News report, titled "Restaurant chains face a challenge of staying relevant," points out that "the younger generations... appear to be reshaping consumer preferences today." It also notes that brands that make a noticeable effort to revamp their businesses—including Red Lobster—are typically rewarded, though not overnight. "Brands and their perception by consumers turn at about the same speed as large supertaker oil freighters," said David Lombardi, a consultant for the company that conducted the study. "It takes some time for consumers to experience the brand for it to show up in the rankings."

Red Lobster also got a significant boost in February—a 33 percent rise in sales—when Beyoncé name-dropped the seafood chain in her single, "Formation." Now all they need is a signature lemonade.